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@article{IVM_1985_5_a12, author = {M. A. Zaretskaya}, title = {The character of the spectrum of quadratic quantum {Hamiltonians}}, journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika}, pages = {68--69}, publisher = {mathdoc}, number = {5}, year = {1985}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/IVM_1985_5_a12/} }
M. A. Zaretskaya. The character of the spectrum of quadratic quantum Hamiltonians. Izvestiâ vysših učebnyh zavedenij. Matematika, no. 5 (1985), pp. 68-69. http://geodesic.mathdoc.fr/item/IVM_1985_5_a12/